arch/powerpc/mm/pgtable_32.c

   1 /*
   2  * This file contains the routines setting up the linux page tables.
   3  *  -- paulus
   4  *
   5  *  Derived from arch/ppc/mm/init.c:
   6  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   7  *
   8  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
   9  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  10  *    Copyright (C) 1996 Paul Mackerras
  11  *
  12  *  Derived from "arch/i386/mm/init.c"
  13  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  14  *
  15  *  This program is free software; you can redistribute it and/or
  16  *  modify it under the terms of the GNU General Public License
  17  *  as published by the Free Software Foundation; either version
  18  *  2 of the License, or (at your option) any later version.
  19  *
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/types.h>
  25 #include <linux/mm.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/init.h>
  28 #include <linux/highmem.h>
  29 #include <linux/memblock.h>
  30 #include <linux/slab.h>
  31
  32 #include <asm/pgtable.h>
  33 #include <asm/pgalloc.h>
  34 #include <asm/fixmap.h>
  35 #include <asm/io.h>
  36 #include <asm/setup.h>
  37
  38 #include "mmu_decl.h"
  39
  40 unsigned long ioremap_base;
  41 unsigned long ioremap_bot;
  42 EXPORT_SYMBOL(ioremap_bot);     /* aka VMALLOC_END */
  43
  44 #if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
  45 #define HAVE_BATS       1
  46 #endif
  47
  48 #if defined(CONFIG_FSL_BOOKE)
  49 #define HAVE_TLBCAM     1
  50 #endif
  51
  52 extern char etext[], _stext[];
  53
  54 #ifdef HAVE_BATS
  55 extern phys_addr_t v_mapped_by_bats(unsigned long va);
  56 extern unsigned long p_mapped_by_bats(phys_addr_t pa);
  57 void setbat(int index, unsigned long virt, phys_addr_t phys,
  58             unsigned int size, int flags);
  59
  60 #else /* !HAVE_BATS */
  61 #define v_mapped_by_bats(x)     (0UL)
  62 #define p_mapped_by_bats(x)     (0UL)
  63 #endif /* HAVE_BATS */
  64
  65 #ifdef HAVE_TLBCAM
  66 extern unsigned int tlbcam_index;
  67 extern phys_addr_t v_mapped_by_tlbcam(unsigned long va);
  68 extern unsigned long p_mapped_by_tlbcam(phys_addr_t pa);
  69 #else /* !HAVE_TLBCAM */
  70 #define v_mapped_by_tlbcam(x)   (0UL)
  71 #define p_mapped_by_tlbcam(x)   (0UL)
  72 #endif /* HAVE_TLBCAM */
  73
  74 #define PGDIR_ORDER     (32 + PGD_T_LOG2 - PGDIR_SHIFT)
  75
  76 pgd_t *pgd_alloc(struct mm_struct *mm)
  77 {
  78         pgd_t *ret;
  79
  80         /* pgdir take page or two with 4K pages and a page fraction otherwise */
  81 #ifndef CONFIG_PPC_4K_PAGES
  82         ret = kzalloc(1 << PGDIR_ORDER, GFP_KERNEL);
  83 #else
  84         ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
  85                         PGDIR_ORDER - PAGE_SHIFT);
  86 #endif
  87         return ret;
  88 }
  89
  90 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  91 {
  92 #ifndef CONFIG_PPC_4K_PAGES
  93         kfree((void *)pgd);
  94 #else
  95         free_pages((unsigned long)pgd, PGDIR_ORDER - PAGE_SHIFT);
  96 #endif
  97 }
  98
  99 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 100 {
 101         pte_t *pte;
 102         extern int mem_init_done;
 103         extern void *early_get_page(void);
 104
 105         if (mem_init_done) {
 106                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 107         } else {
 108                 pte = (pte_t *)early_get_page();
 109                 if (pte)
 110                         clear_page(pte);
 111         }
 112         return pte;
 113 }
 114
 115 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 116 {
 117         struct page *ptepage;
 118
 119         gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
 120
 121         ptepage = alloc_pages(flags, 0);
 122         if (!ptepage)
 123                 return NULL;
 124         pgtable_page_ctor(ptepage);
 125         return ptepage;
 126 }
 127
 128 void __iomem *
 129 ioremap(phys_addr_t addr, unsigned long size)
 130 {
 131         return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED,
 132                                 __builtin_return_address(0));
 133 }
 134 EXPORT_SYMBOL(ioremap);
 135
 136 void __iomem *
 137 ioremap_wc(phys_addr_t addr, unsigned long size)
 138 {
 139         return __ioremap_caller(addr, size, _PAGE_NO_CACHE,
 140                                 __builtin_return_address(0));
 141 }
 142 EXPORT_SYMBOL(ioremap_wc);
 143
 144 void __iomem *
 145 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
 146 {
 147         /* writeable implies dirty for kernel addresses */
 148         if (flags & _PAGE_RW)
 149                 flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
 150
 151         /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
 152         flags &= ~(_PAGE_USER | _PAGE_EXEC);
 153
 154 #ifdef _PAGE_BAP_SR
 155         /* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format
 156          * which means that we just cleared supervisor access... oops ;-) This
 157          * restores it
 158          */
 159         flags |= _PAGE_BAP_SR;
 160 #endif
 161
 162         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 163 }
 164 EXPORT_SYMBOL(ioremap_prot);
 165
 166 void __iomem *
 167 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 168 {
 169         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 170 }
 171
 172 void __iomem *
 173 __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
 174                  void *caller)
 175 {
 176         unsigned long v, i;
 177         phys_addr_t p;
 178         int err;
 179
 180         /* Make sure we have the base flags */
 181         if ((flags & _PAGE_PRESENT) == 0)
 182                 flags |= PAGE_KERNEL;
 183
 184         /* Non-cacheable page cannot be coherent */
 185         if (flags & _PAGE_NO_CACHE)
 186                 flags &= ~_PAGE_COHERENT;
 187
 188         /*
 189          * Choose an address to map it to.
 190          * Once the vmalloc system is running, we use it.
 191          * Before then, we use space going down from ioremap_base
 192          * (ioremap_bot records where we're up to).
 193          */
 194         p = addr & PAGE_MASK;
 195         size = PAGE_ALIGN(addr + size) - p;
 196
 197         /*
 198          * If the address lies within the first 16 MB, assume it's in ISA
 199          * memory space
 200          */
 201         if (p < 16*1024*1024)
 202                 p += _ISA_MEM_BASE;
 203
 204 #ifndef CONFIG_CRASH_DUMP
 205         /*
 206          * Don't allow anybody to remap normal RAM that we're using.
 207          * mem_init() sets high_memory so only do the check after that.
 208          */
 209         if (mem_init_done && (p < virt_to_phys(high_memory)) &&
 210             !(__allow_ioremap_reserved && memblock_is_region_reserved(p, size))) {
 211                 printk("__ioremap(): phys addr 0x%llx is RAM lr %pf\n",
 212                        (unsigned long long)p, __builtin_return_address(0));
 213                 return NULL;
 214         }
 215 #endif
 216
 217         if (size == 0)
 218                 return NULL;
 219
 220         /*
 221          * Is it already mapped?  Perhaps overlapped by a previous
 222          * BAT mapping.  If the whole area is mapped then we're done,
 223          * otherwise remap it since we want to keep the virt addrs for
 224          * each request contiguous.
 225          *
 226          * We make the assumption here that if the bottom and top
 227          * of the range we want are mapped then it's mapped to the
 228          * same virt address (and this is contiguous).
 229          *  -- Cort
 230          */
 231         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 232                 goto out;
 233
 234         if ((v = p_mapped_by_tlbcam(p)))
 235                 goto out;
 236
 237         if (mem_init_done) {
 238                 struct vm_struct *area;
 239                 area = get_vm_area_caller(size, VM_IOREMAP, caller);
 240                 if (area == 0)
 241                         return NULL;
 242                 area->phys_addr = p;
 243                 v = (unsigned long) area->addr;
 244         } else {
 245                 v = (ioremap_bot -= size);
 246         }
 247
 248         /*
 249          * Should check if it is a candidate for a BAT mapping
 250          */
 251
 252         err = 0;
 253         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 254                 err = map_page(v+i, p+i, flags);
 255         if (err) {
 256                 if (mem_init_done)
 257                         vunmap((void *)v);
 258                 return NULL;
 259         }
 260
 261 out:
 262         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 263 }
 264 EXPORT_SYMBOL(__ioremap);
 265
 266 void iounmap(volatile void __iomem *addr)
 267 {
 268         /*
 269          * If mapped by BATs then there is nothing to do.
 270          * Calling vfree() generates a benign warning.
 271          */
 272         if (v_mapped_by_bats((unsigned long)addr)) return;
 273
 274         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 275                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 276 }
 277 EXPORT_SYMBOL(iounmap);
 278
 279 int map_page(unsigned long va, phys_addr_t pa, int flags)
 280 {
 281         pmd_t *pd;
 282         pte_t *pg;
 283         int err = -ENOMEM;
 284
 285         /* Use upper 10 bits of VA to index the first level map */
 286         pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
 287         /* Use middle 10 bits of VA to index the second-level map */
 288         pg = pte_alloc_kernel(pd, va);
 289         if (pg != 0) {
 290                 err = 0;
 291                 /* The PTE should never be already set nor present in the
 292                  * hash table
 293                  */
 294                 BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) &&
 295                        flags);
 296                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 297                                                      __pgprot(flags)));
 298         }
 299         return err;
 300 }
 301
 302 /*
 303  * Map in a chunk of physical memory starting at start.
 304  */
 305 void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
 306 {
 307         unsigned long v, s, f;
 308         phys_addr_t p;
 309         int ktext;
 310
 311         s = offset;
 312         v = PAGE_OFFSET + s;
 313         p = memstart_addr + s;
 314         for (; s < top; s += PAGE_SIZE) {
 315                 ktext = ((char *) v >= _stext && (char *) v < etext);
 316                 f = ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL;
 317                 map_page(v, p, f);
 318 #ifdef CONFIG_PPC_STD_MMU_32
 319                 if (ktext)
 320                         hash_preload(&init_mm, v, 0, 0x300);
 321 #endif
 322                 v += PAGE_SIZE;
 323                 p += PAGE_SIZE;
 324         }
 325 }
 326
 327 void __init mapin_ram(void)
 328 {
 329         unsigned long s, top;
 330
 331 #ifndef CONFIG_WII
 332         top = total_lowmem;
 333         s = mmu_mapin_ram(top);
 334         __mapin_ram_chunk(s, top);
 335 #else
 336         if (!wii_hole_size) {
 337                 s = mmu_mapin_ram(total_lowmem);
 338                 __mapin_ram_chunk(s, total_lowmem);
 339         } else {
 340                 top = wii_hole_start;
 341                 s = mmu_mapin_ram(top);
 342                 __mapin_ram_chunk(s, top);
 343
 344                 top = memblock_end_of_DRAM();
 345                 s = wii_mmu_mapin_mem2(top);
 346                 __mapin_ram_chunk(s, top);
 347         }
 348 #endif
 349 }
 350
 351 /* Scan the real Linux page tables and return a PTE pointer for
 352  * a virtual address in a context.
 353  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 354  * the PTE pointer is unmodified if PTE is not found.
 355  */
 356 int
 357 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
 358 {
 359         pgd_t   *pgd;
 360         pud_t   *pud;
 361         pmd_t   *pmd;
 362         pte_t   *pte;
 363         int     retval = 0;
 364
 365         pgd = pgd_offset(mm, addr & PAGE_MASK);
 366         if (pgd) {
 367                 pud = pud_offset(pgd, addr & PAGE_MASK);
 368                 if (pud && pud_present(*pud)) {
 369                         pmd = pmd_offset(pud, addr & PAGE_MASK);
 370                         if (pmd_present(*pmd)) {
 371                                 pte = pte_offset_map(pmd, addr & PAGE_MASK);
 372                                 if (pte) {
 373                                         retval = 1;
 374                                         *ptep = pte;
 375                                         if (pmdp)
 376                                                 *pmdp = pmd;
 377                                         /* XXX caller needs to do pte_unmap, yuck */
 378                                 }
 379                         }
 380                 }
 381         }
 382         return(retval);
 383 }
 384
 385 #ifdef CONFIG_DEBUG_PAGEALLOC
 386
 387 static int __change_page_attr(struct page *page, pgprot_t prot)
 388 {
 389         pte_t *kpte;
 390         pmd_t *kpmd;
 391         unsigned long address;
 392
 393         BUG_ON(PageHighMem(page));
 394         address = (unsigned long)page_address(page);
 395
 396         if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
 397                 return 0;
 398         if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
 399                 return -EINVAL;
 400         __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
 401         wmb();
 402         flush_tlb_page(NULL, address);
 403         pte_unmap(kpte);
 404
 405         return 0;
 406 }
 407
 408 /*
 409  * Change the page attributes of an page in the linear mapping.
 410  *
 411  * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
 412  */
 413 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 414 {
 415         int i, err = 0;
 416         unsigned long flags;
 417
 418         local_irq_save(flags);
 419         for (i = 0; i < numpages; i++, page++) {
 420                 err = __change_page_attr(page, prot);
 421                 if (err)
 422                         break;
 423         }
 424         local_irq_restore(flags);
 425         return err;
 426 }
 427
 428
 429 void kernel_map_pages(struct page *page, int numpages, int enable)
 430 {
 431         if (PageHighMem(page))
 432                 return;
 433
 434         change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
 435 }
 436 EXPORT_SYMBOL_GPL(kernel_map_pages);
 437 #endif /* CONFIG_DEBUG_PAGEALLOC */
 438
 439 static int fixmaps;
 440
 441 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 442 {
 443         unsigned long address = __fix_to_virt(idx);
 444
 445         if (idx >= __end_of_fixed_addresses) {
 446                 BUG();
 447                 return;
 448         }
 449
 450         map_page(address, phys, pgprot_val(flags));
 451         fixmaps++;
 452 }
 453
 454 void __this_fixmap_does_not_exist(void)
 455 {
 456         WARN_ON(1);
 457 }